This invention relates generally to quick-connect couplings and more particularly to a quick-connect coupling which is especially adapted for use in applications involving a combustible gas (e.g., natural or LP gas).
Gas appliances such as dryers, stoves and the like are commonplace items in many homes. Typically, an appliance is connected to a gas supply by a coupling comprising various component parts which have to be screwed and unscrewed in order to connect and disconnect the appliance from the source. This is a relatively burdensome and time-consuming task with the potential for leakage if the connection is not tightly secured.
The use of a quick-connect coupling between the gas supply line and the appliance has been suggested as a solution to the above-mentioned problem. One particular coupling which has been proposed for such use includes a socket fitting for connection to the gas line and a plug fitting or nipple for connection to the appliance. The socket fitting has a gas flow passage therethrough, a poppet valve in the flow passage spring biased toward a closed position, and, as required by the National Fuel Gas Code, a manually operable ball valve upstream from the poppet valve, the ball valve being manually movable by means of a lever on the socket fitting from a fully open position, through a range of movement in which it is only partially open, to a fully closed position. The poppet valve automatically opens against the bias of its spring when the nipple component of the coupling is inserted into the socket. A sleeve slidably mounted on the socket fitting is movable from a retracted position for permitting the nipple component to be inserted in the socket, to a locking position in which the nipple is held captive in the socket, and then back to a retracted position for removal of the nipple component from the socket. The nipple component cannot be inserted into the socket to connect the appliance to the gas line unless the sleeve is in its retracted position. Similarly, the components cannot be disconnected unless the sleeve is moved from its locking to its retracted position. In an attempt to avoid leakage of gas during connection and disconnection of the coupling, the design of the coupling is such that the sleeve cannot be moved to its retracted position when the lever of the ball valve is fully open. However, the arrangement is such that the sleeve can be retracted when the ball valve is partially open. As a result, there is risk of leakage of gas during connection and disconnection of the coupling components.
Accordingly, there is a need for a quick-connect coupling which eliminates any risk of gas leakage during connection and disconnection of the appliance to the gas line.